This invention relates to apparatus for and methods of stabilizing a leaking dam or levee, and particularly relates to apparatus for and methods of stopping leaks through dams such as, for example, earth dams, typically located along the banks of quiescent bodies of water, and levees along waterways, which contain moving water.
A quiescent body of water typically includes lakes, reservoirs, and the like, which are contained within a completely enclosing shoreline, where, normally the water does not escape or flow from within the quiescent body. Waterways of moving water include canals, rivers, and the like, where the water is typically continuously flowing along the banks thereof, which confines the flowing water between the banks, where the flowing water eventually empties into a larger body of water such as, for example, a sea or an ocean.
As long as there are no incidents which cause the level of the water to rise in the quiescent bodies and waterways, the water remains within the defined boundaries of the shoreline and banks, respectively. However, weather-related incidents, such as, for example, wind storms and rain, can result in excess amounts of water along at least sections of the quiescent bodies and the waterways, where the water level thereof extends beyond the shoreline and the banks, respectively, resulting in devastating flooding of areas adjacent the bodies and waterways. Such flooding is widely known for causing loss of life and property damage.
Naturally formed dams and levees are typically formed as a consequence of flooding over the shoreline and banks, where sediment is deposited, and results in protective barriers which are higher than the floodplain for that area. Man-made dams and levees are constructed purposely to be higher than the floodplains, and may be constructed with concrete, rocks, soil, and the like. Dams and levees formed by compacted soil, and the like, are typically referred to as earth dams and levees, and are susceptible to breaches in the soil, which weaken and erode the protective features of the earth dams and levees. While the major constituent of earth dams is compacted soil, such dams may also include a limited amount of rocks, pebbles, and the like.
For purposes of brevity, and not by way of limitation, a dam and a levee will be referred to hereinafter as “a dam.”
In the past, as a technique for minimizing, or even preventing, the disasterous flooding events noted above, dams have been built around the quiescent bodies of water, and along the banks of the waterways, to increase the level to which the water is allowed to rise before becoming a flooding threat to nearby people and property. While man-made dams composed of concrete and the like are generally considered as breach-free structures, breaches do occur in such dams, thereby lessening the integrity of the dam. However, as noted above, man-made and natural dams, composed primarily of compacted soil, are particularly susceptible, under the hydrostatic pressure of the contained body of water, to erosion. Such erosion causes leaks through the dams, which could cause the dams to collapse in the vicinity of the erosion. Therefore, earth dams require constant surveillance, and repair, to maintain the integrity of such dams.
Consequently, there is a need for an apparatus for, and methods of, facilitating the stopping of the undesirable leakage of water within, and through, a breach in the structure of a dam to maintain and stabilize the integrity of the dam for continued use.
Further, there is a need for an apparatus for, and methods of, facilitating temporary stopping of the undesirable leakage of water within, and through, a breach in the structure of a dam to preclude the flow of water through the breach, and to maintain and stabilize the integrity of the dam, during a period when the breach-containing portion of the dam is being repaired.
An article, written by Mike Field, titled, “Fragile Foundations,” which appeared in “Johns Hopkins Engineering, The Magazine of the Johns Hopkins Whiting School of Engineering, ” Winter 2010, starting on page 12, refers to the biennial report card of the American Society of Civil Engineers on the state of America's infrastructure in 2009, including dams and levees. As noted in the article, “Thousands of the nation's dams, for instance, are rated structurally deficient, and no fewer than 1800 of those are rated “high hazard” dams, meaning their catastrophic failure would result in significant loss of life.”
In today's economic climate, it is highly unlikely that such a large infrastructure investment will be made.
Consequently, there is a need for a relatively low cost apparatus for and methods of facilitating the stabilization and maintenance of the nation's dams, particularly during a period when it appears that high-cost repairs and reconstruction to such “high hazard” dams may not be forthcoming.
As shown and described in U.S. Pat. No. 4,184,786 (the '786 patent), which issued on Jan. 22, 1980, a water-impervious, flexible cover is placed over surfaces of an earth dam to protect vulnerable surfaces of the dam from developing breaches. The cover extends over at least the top surface and the downstream surface of the dam, and preferably extends over the upstream surface of the dam as well. Also, the cover extends to, and is anchored at the bed of the body of the water on the downstream side of the dam, and to the ground on the upstream side of the dam. Such an extensive cover for an entire dam would be very costly in order to protect the entire dam in the manner described in the '786 patent.
Thus, there is a need for cost-effective apparatus of and methods for stabilizing an earth dam in the event of a leak through a breach in the dam.
Also, the type of material of the cover, as described in the '786 patent, is an organic material which may become brittle and crack under prolonged exposure to the environment, including debilitating stresses to which a cover for an earth dam is typically subjected. In particular, organic materials soften and deform irreversibly at temperatures greater than 100° C., and become brittle at temperatures less than −25° C.
Thus, there is a need for an apparatus of and methods for stabilizing an earth dam wherein the material of critical portions of the apparatus are capable of maintaining structural resiliency and integrity when subjected to here-to-fore potentially debilitating stresses.